The Camden journal article (blue link in the first post) has a sound cloud embedded in it.

The soundcloud gives 33 seconds of a recording--

a bit of banjo, then Pete says 'hey, since I'm making a tape recording for you, let me put this funeral song on it for you, you never know, you might sing it if someone dies. [sings] To my old brown earth and to my old blue sky, I will now give these last few molecules of I.'

It's the young Pete voice, singing without any banjo, slowly and quietly, and just to one person to make the tape, so poignant now.